Illusory depth perception of oblique lines produced by overlaid vertical disparity

Ito, Hiroyuki

doi:10.1016/j.visres.2004.10.008

Cited by 7 publications

(5 citation statements)

References 25 publications

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“…In any case, disparity projection calculation provides an alternative account. It straightforwardly predicts Ito's (2005) results for both vertical and horizontal dot disparities. It would also apply to intermediate dot disparity directions, whatever their combination of horizontal and vertical components.…”

Section: Discussionmentioning

confidence: 53%

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From disparity to depth: How to make a grating and a plaid appear in the same depth plane

Chai

Farell

2009

Journal of Vision

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Even though binocular disparity is a very well-studied cue to depth, the function relating disparity and perceived depth has been characterized only for the case of horizontal disparities. We sought to determine the general relationship between disparity and depth for a particular set of stimuli. The horizontal disparity direction is a special case, albeit an especially important one. Non-horizontal disparities arise from a number of sources under natural viewing condition. Moreover, they are implicit in patterns that are one-dimensional, such as gratings, lines, and edges, and in one-dimensional components of two-dimensional patterns, where a stereo matching direction is not well-defined. What function describes perceived depth in these cases? To find out, we measured the phase disparities that produced depth matches between a reference stimulus and a test stimulus. The reference stimulus was two-dimensional, a plaid; the test stimulus was one-dimensional, a grating. We find that horizontal disparity is no more important than other disparity directions in determining depth matches between these two stimuli. As a result, a grating and a plaid appear equal in depth when their horizontal disparities are, in general, unequal. Depth matches are well predicted by a simple disparity vector calculation; they survive changes in component parameters that conserve these vector quantities. The disparity vector rule also describes how the disparities of 1-D components might contribute to the perceived depth of 2-D stimuli.

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Section: Discussionmentioning

confidence: 53%

“…Ito (2005) created a display that showed a combined effect of orientation and vertical disparity on perceived depth. The displays consisted of dots with vertical disparity interspersed among oblique lines with zero disparity.…”

Section: Discussionmentioning

confidence: 99%

From disparity to depth: How to make a grating and a plaid appear in the same depth plane

Chai

Farell

2009

Journal of Vision

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“…However, even if the effective disparity direction were known, the question of how the visual system uses disparity parameters to compute the depth of 1-D stimuli would remain unresolved. Previous studies have assumed, reasonably, that 1-D stimuli have some intrinsic disparity direction and a particular stereoscopic depth that depends on the sign and magnitude of the horizontal component of this disparity, just as for 2-D stimuli (van Ee & Schor, 2000; van Dam & van Ee, 2004; Ito, 2005). However, testing these assumptions requires independently varying the magnitude and the direction of the relative disparity of the 1-D stimulus and a reference stimulus, and this has not been done.…”

Section: Introductionmentioning

confidence: 99%

Projected disparity, not horizontal disparity, predicts stereo depth of 1-D patterns

2009

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Binocular disparities have a straightforward geometric relation to object depth, but the computation that humans use to turn disparity signals into depth percepts is neither straightforward nor well understood. One seemingly solid result, which came out of Wheatstone’s work in the 1830’s, is that the sign and magnitude of horizontal disparity predict the perceived depth of an object: ‘Positive’ horizontal disparities yield the perception of ‘far’ depth, ‘negative’ horizontal disparities yield the perception of ‘near’ depth, and variations in the magnitude of horizontal disparity monotonically increase or decrease the perceived extent of depth. Here we show that this classic link between horizontal disparity and the perception of ‘near’ versus ‘far’ breaks down when the stimuli are one-dimensional. For these stimuli, horizontal is not a privileged disparity direction. Instead of relying on horizontal disparities to determine their depth relative to that of two-dimensional stimuli, the visual system uses a disparity calculation that is non-veridical yet well suited to deal with the joint coding of disparity and orientation.

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“…Equation 1 predicts that an oblique Gabor with the illustrated disparity should produce a depth match. It does ( Chai & Farell, 2009 ; see also Ito, 2005 ). The plaid disparity in Figure 7 D is the same as in Figures 7 A and 7 B.…”

Section: Psychophysical Evidence: 1-d Stimulimentioning

confidence: 99%

What's special about horizontal disparity

Farell

2023

Journal of Vision

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Horizontal disparity has been recognized as the primary signal driving stereoscopic depth since the invention of the stereoscope in the 1830s. It has a unique status in our understanding of binocular vision. The direction of offset of the eyes gives the disparities of corresponding image point locations across the two retinas a strong horizontal bias. Beyond the retina, other factors give shape to the effective disparity direction used by visual mechanisms. The influence of orientation is examined here. I argue that horizontal disparity is an inflection point along a continuum of effective directions, and its role in stereo vision can be reinterpreted. The pointwise geometric justification for its special status neglects the oriented structural elements of spatial vision, its physiological support is equivocal, and psychophysical support of its special status may partially reflect biased stimulus sampling. The literature shows that horizontal disparity plays no particular role in the processing of one-dimensional stimuli, a reflection of the stereo aperture problem. The resulting depth is non-veridical, even non-transitive. Although one-dimensional components contribute to the stereo depth of visual objects generally, two-dimensional stimuli appear not to inherit the aperture problem. However, a look at the two-dimensional stimuli that predominate in experimental studies shows regularities in orientation that give a new perspective on horizontal disparity.

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Illusory depth perception of oblique lines produced by overlaid vertical disparity

Cited by 7 publications

References 25 publications

From disparity to depth: How to make a grating and a plaid appear in the same depth plane

From disparity to depth: How to make a grating and a plaid appear in the same depth plane

Projected disparity, not horizontal disparity, predicts stereo depth of 1-D patterns

What's special about horizontal disparity

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